KEF Q350 Speaker Review

[amirm]

Based on the 3 blind listening tests I've done in my room, this seems like a flaw in the test. IME, you can't place all of the speakers in the same spot. Instead, you should place them in the spot that sounds best for that room.

If a speaker has that much room dependency, odds of someone buying it and being happy goes way down. The beauty of a well measuring speaker is that this issue is hugely lessened.

 

[amirm]

Subjectively, how would you say the Blades compared to the Salon 2s. Salon 2s are one of my dream loudspeakers, but KEFs have seemed to measure really well on this site.

We had them in the same setup. The blades did not reach Salon 2's performance. They sounded dull from what I recall. They were very nice looking though!

 

[richard12511]

Longer term, I am keeping a collection of the budget speakers which I hope can be blind tested with our audiophile society here.

That's awesome. I wouldn't have thought to do that. That's a great idea.

 

[amirm]

The cost is the clutter in my lab to keep them around and money they tie up that I could use for other speakers to test.

 

[richard12511]

I personally am starting to think there's something to Amphion's approach of emphasizing the region from 2-5k, which seems to tie in quite closely with my own tastes.




Though the speakers were centered for the preference studies, from what I can tell not all the research is conducted with centered speakers. The most important thing seems to be consistent coupling with room modes.

In his book, Toole describes one of Harman's test rooms -- maybe the same one Amir was in -- mentioning that the programmable speaker mover "can compare up to four single loudspeakers at one time, up to four stereo pairs, or up to three L, C, R combinations. The single loudspeakers can be compared at L, C, or R locations at varied distances from the side walls. The distance from the front wall is also a controlled variable." See figure 3.13.

In chapter 7.4.2, he talks about one of his studies on directivity, (the one about narrow vs wide and stereo vs mono) and the illustration shown has the speakers at the corners.

What about blinding a speaker that's supposed to be placed against a wall, like the D&D 8C? Would you expect the results of a blind test with that speaker where both the speakers are out in the middle(in the same spot) to be unfairly altered? Perhaps the D&D would win if placed properly next to a wall? especially if it was super close.

 

[MZKM]

We had them in the same setup. The blades did not reach Salon 2's performance. They sounded dull from what I recall. They were very nice looking though!

The on-axis and listening window measure pretty dang well, but for the far off-axis the side-firing drivers cause huge issues in the response, as seen in NRC and Stereophile measurements.

Normalized horizontal directivity from Stereophile:

45/60/75 degree off axis horizontally from SoundStage/NRC:

That said, it usually is a speaker I recommend for those looking in that price range, mainly because it’s visually interesting and I’ve successfully convinced 2 people to purchase them over the Wilson‘s they were considering (they both auditioned both and agreed the KEF was much better).

I wish to speculate how some truly expensive speakers would measure and score on the preference ratings, such as the KEF Muon, Kharma Enigma Veyron EV-1D, Von Schweikert Ultra 11, etc.

 

[richard12511]

Not shure cost and performace wise KEF is really interrested do more about those resonances for Q350 in score actual looks be pretty high and better than the more costly LS50 and if they fine tuned Q350 to even better performance it would add costs and probably performance wise make it close too much in on R3 as seen in below animation, as tuga and napilopez hinted from sterophile's measurement there looks be technical proof that resonance can come from port noice but also a driver position right in the middle of a sharp edged enclosure for this combination of dimensions show heavy +3dB baffle diffraction boost centered around 1kHz point.
View attachment 64491

The R3 seems like a clear upgrade, yet it's clear they were aiming for the same target. Sign of a good brand, imo.

 

[richard12511]

If a speaker has that much room dependency, odds of someone buying it and being happy goes way down. The beauty of a well measuring speaker is that this issue is hugely lessened.

In our case, it was because we were doing a stereo blind test. The different dispersion patterns dictated different widths and toe ins. I think a mono test is much easier in this regard, since you don't have to worry about imaging.

However, my point was more towards the more unusual designs that are designed with specific placement in mind. Honestly, I've never heard one, but what about speakers like the D&D 8C and Kii 3? Aren't they supposed to be placed right up against a wall? If they weren't in the mono test, wouldn't that affect the outcome? I would certainly classify those two speakers as a "well measuring speaker".

 

[mhardy6647]

Odd (disheartening, actually) to see that KEF would get clarity and detail wrong. That was one of the company's hallmarks "BITD" (as they say).

borrowed image of a pretty pair of KEF 104aB loudspeakers from: https://audiokarma.org/forums/index.php?threads/kef-104ab-one-more-time.864834/

 

[richard12511]

We had them in the same setup. The blades did not reach Salon 2's performance. They sounded dull from what I recall. They were very nice looking though!

Thanks. That's kinda what I had assumed, but it's also good to hear.

In a weird way, it seems like KEF is more closely following Toole/Olive science than Revel(at least the stuff they made public). Revel seems to be targeting wider dispersion, at the expense of smooth directivity, and so far(at least to your ears), that seems like a good trade.

 

[Zvu]

I'm going to guess those two resonances would should up in a nearfield port response. Tends to be the case for resonances around 1k in my experience. Should hopefully be EQable with a little effort.

Source: https://www.hifialex.de/pimp-kef-q350/

 

[napilopez]

Source: https://www.hifialex.de/pimp-kef-q350/

Hah! There you go.

What about blinding a speaker that's supposed to be placed against a wall, like the D&D 8C? Would you expect the results of a blind test with that speaker where both the speakers are out in the middle(in the same spot) to be unfairly altered? Perhaps the D&D would win if placed properly next to a wall? especially if it was super close.

Yeah, I'm not sure how that would work exactly in practice, but again, the room allows them to adjust the distance to the front wall. So it might not be quite apples to apples but they should be able to account for that.

 

[wwenze]

Not shure cost and performace wise KEF is really interrested do more about those resonances for Q350 in score actual looks be pretty high and better than the more costly LS50 and if they fine tuned Q350 to even better performance it would add costs and probably performance wise make it close too much in on R3 as seen in below animation, as tuga and napilopez hinted from sterophile's measurement there looks be technical proof that resonance can come from port noice but also a driver position right in the middle of a sharp edged enclosure for this combination of dimensions show heavy +3dB baffle diffraction boost centered around 1kHz point.
View attachment 64491

So the curves in LS50 that seemed to make the cabinet needlessly large has some use

Can we fix this via aftermarket tweaks? Maybe we can add some curves or boobs that hang off the top of the speaker.

It will be a whole new unexplored market, and one with measurable effects.

 

[Mawclaw]

You mean your "port" interfering with the speaker's???

I chuff. Big time.

 

[ROOSKIE]

Can't wait to see the comments on this one.

On a more serious note, see how much nicer the veneer is on these compared to the JBL hdi we saw recently.

In person the veneer (on the Q350)looked very cheap to me. It is a very fake looking woodgrain. Very disappointed because I liked the images online, zero interest after seeing it up close.

 

[aarons915]

Source: https://www.hifialex.de/pimp-kef-q350/

Of course this wouldn't be an option for the Q series but for those who aren't aware of how KEF dealt with this problem in the LS50, here is a snip of the port output with a rigid tube compared to a flexible wall used in the LS50. I wonder if this means just using the Port plug and removing the "donut hole" in the middle, you could achieve something similar at the loss of a bit of output in the bass. This is from the LS50 Whitepaper FYI.

 

[ROOSKIE]

In our case, it was because we were doing a stereo blind test. The different dispersion patterns dictated different widths and toe ins. I think a mono test is much easier in this regard, since you don't have to worry about imaging.

However, my point was more towards the more unusual designs that are designed with specific placement in mind. Honestly, I've never heard one, but what about speakers like the D&D 8C and Kii 3? Aren't they supposed to be placed right up against a wall? If they weren't in the mono test, wouldn't that affect the outcome? I would certainly classify those two speakers as a "well measuring speaker".

If you are willing to move your speakers around for the best sound then that is the way to go, no doubt. I would personally give priority to my gear over anything else.
For folks who can not do that then it is best to find a speaker that doesn't need exact placements and is flexible. I think that is what this site is trying to do in general in terms of the rating system. Some of the rating system goes out the window if you are going to be able to work the room around the speakers and especially if you get into Dirac or EQ and stuff like that.
The measurements still indicate where you can go but you'll have to remember to ignore some of the subjective comments and the rating.

 

[GXAlan]

The cost is the clutter in my lab to keep them around and money they tie up that I could use for other speakers to test.

You need to leverage advertising/commission on Amazon links to music (not hardware) or other high priced stuff like cameras. As long as you're not putting links to audio gear, I think people would still think that it's fair/objective.

 

[Juhazi]

Two way BR speakers really do have problems with port noise around 1kHz. Studies usually concentrate on what happens around tuning frequency and about max pressure/spl fow characteristics. A bent port and placement of the inner orifice are crucial to noise, and in practise you must just try different configurations - diy!

http://jahonen.kapsi.fi/Audio/Papers/AES_PortPaper.pdf
https://www.tandfonline.com/doi/full/10.1080/19942060.2016.1277166
https://www.researchgate.net/public..._to_harmonic_excitation_and_remedial_measures

Abstract
At high sound pressure levels a bass-reflex port produces blowing sounds, especially in the case of small loudspeaker boxes with narrow bass-reflex ports. The blowing sounds are caused by vortex shedding of the acoustic flow at the end of the port at high flow velocities. It has been found that acoustic standing waves in the longitudinal direction of the port are excited in a pulsatile manner by the periodically generated vortices. This is demonstrated by time history measurements of the blowing sounds of a loudspeaker system with a bass-reflex port driven by a harmonic signal. Broadband turbulence sound appears to be weaker than these deterministic sounds. It has been found that, near the 1-kHz port resonance frequency, the power level of the blowing sounds can be reduced by 8 dB by using a port cross section that diverges gradually toward both port ends with a slope angle at the port ends of about 6 degrees, and rounding the edges at both port ends. (C) 1998 Acoustical Society of America. [S0001-4966(98)00909-6]

 

[QMuse]

So in that regard, I am operating blind, albeit with having the graphs in hand.

That can hardly be called blind.